I had no issues with Win 10 until about a month ago that I got resolved with a support technician and I was given a new product key. However, I didn't have the chance to write it down as it was copied and pasted by the technician himself. Today, however, i try to boot my computer and the only thing that I get is "Missing Operating System." I don't know what to do and i spoke to another technician who only gave me a list of numbers for a support desk. I don't want to go that far, and hoping it can be resolved soon. Please help?